VOLUME3 Organic Molecular Photochemistry edited by V. Ram am ur thy Tulane University New Orleans, Louisiana KirkS. Schanze University of Florida Gainesville, Florida n MARCEL MARCEl DEKKER, INc. NEw YoRK • BASEl DEKKER ' ISBN: 0-8247-6606-7 This book is printed on acid-free paper. Headquarters Marcel Dekker, Inc. 270 Madison Avenue, New York, NY 10016 tel: 212-696-9000; fax: 212-685-4540 Eastern Hemisphere Distribution Marcel Dekker AG Hutgasse 4, Postfach 812, CH-4001 Basel, Switzerland tel: 41-61-261-8482; fax: 41-61-261-8896 World Wide Web http://www.dekker.com The publisher offers discounts on this book when ordered in bulk quantities. For more information, write to Special Sales/Professional Marketing at the headquar ters address above. Copyright © 1999 by Marcel Dekker, Inc. All Rights Reserved. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without per mission in writing from the publisher. Current printing (last digit): 10987654321 PRINTED IN THE UNITED STATES OF AMERICA Preface The third volume in the Molecular and Supramolecular Photochemistry series focuses on organic molecular photochemistry. This volume presents six chapters in the general area of photochemical and photophysical studies of organic mole cules. Although the thrust of the individual chapters vary, each deals with the excited-state behavior of organic molecules in their molecular form. Tremendous activity in photochemical studies over the past 40 years has resulted in a reasonable understanding of the photobehavior of a large number of organic molecules, in the discovery of innumerable reactions, and in establish ing the basic mechanistic framework for a large number of photoreactions. Such a rapid development has resulted in photoscience becoming a tool in the hands of chemists who want to exploit light for useful ends. Because of this, there is a need to periodically consolidate and critically evaluate the infonnation that becomes available through the tireless efforts of our colleagues. The Molecular and Supramolecular Photochemistry series aims to serve this role. In Volume 3 of this series, Organic Molecular Photochemistry, eight active photochemists summarize and critically evaluate the literature in their area of expertise. Chapters 3 and 4 deal with a well-investigated and important reaction in photochemistry: geometric isomerization. Arai (Chap. 3) deals with the one way cis-trans isomerization of tuyl-substituted alkenes. Rao (Chap. 4) summa rizes recent mechanistic developmenta in the area of geometric isomerization of olefins. These two chapters combined provide over 300 references that should Ill lv Preface be valuable to those seeking current knowledge of the excited-state geometric isomerization of olefins. It is unnecessary to remind the readers that one of the classic reviews on geometric isomerization, by Saltiel and coworkers, appeared in an earlier version of this series (Org. Photochem., 1973, 3, 1). One of the important activities of chemists is to seek similarity among apparent dissimilarity. Fleming and Pincock have successfully done this in their chapter on photochemical cleavage reactions. Cleavage of the C-X bond prompted by light has been investigated by a number of workers (X being different in each case) and mechanisms for the cleavage process have been proposed. Further progress in the field depends on one's ability to connect all that is known on the photocleavage process. Fleming and Pincock have effi ciently achieved this in Chapter 5. This chapter, along with one by Cristo! and Bindel that appeared in the Organic Photochemistry series (1983, 6, 327), is indispensable to those interested in basic mechanistic studies of cleavage process, as well as phototriggers, photocleavages, photoaffinity labels, and photoacid generation. Despite intense activity in discovering new reactions and establishing mechanisms of photoreactions, control of the chirality of photoproducts is still unknown. While strategies for achieving high (e.e., >95%) asymmetric induction in a number of thermal reactions have been developed, such is not the case for reactions initiated by light. Activity in this area can certainly be expected in the coming years. The chapter by Everitt and Inoue (Chap. 2) provides a thorough critical summary of the literature on asymmetric photoreactions in solution. This chapter, along with a previous review by Inoue (Chern. Rev., 1992, 92, 741), should be a valuable information package in the hands of photochemists wishing knowledge of asymmetric photochemistry. Although the field of photochemistry has reached its maturity, certain criti cal gaps in our understanding of the photobehavior of molecules in organized assemblies exist. Two chapters are devoted to presenting the current status of activities in this area. Ito (Chap. 1) provides a summary of the literature on solid state photoreactions of two component crystals. The literature in this area is quite spread out and Ito has done a wonderful job of distilling it into a single chapter. Molecular photochemistry has been a valuable tool in characterizing the interior of organized assemblies in terms of the parameters that we use to understand isotropic solvents. Bhattacharyya (Chap. 6) provides a critical evaluation of the various probes and their photoproperties that can be used to understand the reaction cavities of organized assemblies such as zeolites, cyclodextrins, and micelles. It is our hope that the chapters presented in this volume will serve not only as a valuable resource for experts and active workers, but also as supplementary reading material for graduate students. As editors we have enjoyed reading the Preface v work of the authors, who have done a wonderful job of presenting interesting and current material in a critical and consolidated manner. We hope that you will benefit from this book and support this series. V. Ramamurthy Kirk S. Schanze This Page Intentionally Left Blank Contents Preface iii Contributors ix 1. Solid-State Organic Photochemistry of Mixed Molecular Crystals 1 Yoshikatsu Ito 2. Asymmetric Photochemical Reactions in Solution 71 Simon R. L. Everitt and Yoshihisa Inoue 3. Photochemical cis-trans Isomerization in the Triplet State 131 Tatsuo Arai 4. Photochemical cis-trans Isomerization from the Singlet Excited ~te 1@ V. Jayathirtha Rao 5. Photochemical Cleavage Reactions of Benzyl-Heteroatom Sigma Bonds 211 Steven A. Fleming and James A. Pincock vii viii Contents 6. Photophysical Probes for Organized Assemblies 283 Kankan Bhattacharyya Index 341 Contributors Tatsuo Arai, Ph.D. Department of Chemistry, University of Tsukuba, Tsu kuba, lbaraki, Japan Kankan Bhattacharyya, Ph.D. Physical Chemistry Department, Indian Asso ciation for the Cultivation of Science, Calcutta, India Simon R. L. Everitt, Ph.D. Inoue Photochirogenesis Project, ERATO, Japan Science and Technology Corporation and Osaka University, Toyonaka, Japan Steven A. Fleming, Ph.D. Department of Chemistry and Biochemistry, Brig ham Young University, Provo, Utah Yoshihisa Inoue, Ph.D. Inoue Photochirogenesis Project, ERATO, Japan Sci ence and Technology Corporation and Osaka University, Toyonaka, Japan Yoshikatsu Ito, Ph.D. Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan James A. Pincock, Ph.D. Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada V. Jayathirtha Rao, Ph.D. Organic Chemistry Division II, Indian Institute of Chemical Technology, Hyderabad, India lx